1. Field of the Invention
Embodiments of the invention described herein pertain to the field of computer systems and methods. More particularly, but not by way of limitation, one or more embodiments of the invention enable a method of and system for determining a data model designed for being superposed with an image of a real object in an object tracking process.
2. Description of the Related Art
Augmented Reality Systems permit the superposition of computer-generated virtual information with visual impressions of the real environment. To this end, the visual impressions of the real world are mixed with virtual information, e.g. by means of semi-transmissive data glasses worn on the head of a user. The blending-in of virtual information or objects can be effected in context-dependent manner, i.e. matched to and derived from the respective environment viewed. As virtual information, it is basically possible to use any type of data, such as texts, images etc. The real environment is detected e.g. with the aid of a camera carried on the head of the user.
When the person using an augmented reality system turns his or her head, tracking of all virtual objects is necessary with respect to the changing field of view. The real environment may be a complex apparatus, and the object detected can be a significant member of the apparatus. During an ensuing, so-called tracking operation, which represents the working process proper of the object tracking operation, while context-dependent information is blended-in in a display device for the user of the system at a desired location with respect to the real environment, the real object detected during initialization serves as a reference for computing the position at which the virtual information is to be displayed or blended-in in an image or picture taken up by the camera. Due to the fact that the user may change his or her position and orientation, the real object has to be subjected to continuous tracking in order to display the virtual information at the correct position in the display device also in case of an altered position and/or altered orientation of the user. The effect achieved thereby is that the information, irrespective of the position and/or orientation of the user, is displayed in the display device in context-correct manner with respect to reality. An augmented reality system in this regard is an example of the utilization of such so-called markerless tracking systems.
One of the major problems in the field of augmented reality is the determination of the head position and the head orientation of the user (pose) by means of a video camera that is rigidly joined to the head. This problem is related with, and may be converted to, the problem of object tracking which, as described hereinbefore, is concerned with the determination of the pose of an object with respect to the video camera, using only the video flow or image flow of the video camera as source of information.
To solve this problem, one method has turned out to be particularly promising in practical application, which is known as so-called contour-based object tracking. In this method, a so-called contour model of the real object to be tracked is compared to its image in a video representation and is matched until optimum conformity has been established (optimization). However, there are hardly investigations known so far as to how such contour models can be provided in efficient manner. In the methods of contour-based tracking known so far, such contour models are generated manually, making use of the respective real objects. Such a manual generation of a data model of virtual information, which is designed for being superposed with an image of a real object, is however comparatively complex and involves much time.